Select the correct answer.

Which of the following functions is the inverse of this function?
[tex]\[ f(x)=\frac{x+2}{7} \][/tex]

A. [tex]\[ p(x)=7x-2 \][/tex]

B. [tex]\[ q(x)=\frac{-x+2}{7} \][/tex]

C. [tex]\[ r(x)=\frac{7}{x+2} \][/tex]

D. [tex]\[ s(x)=2x+7 \][/tex]



Answer :

To determine the inverse of the function [tex]\( f(x) = \frac{x + 2}{7} \)[/tex], we will follow a step-by-step method to find the function that, when composed with [tex]\( f(x) \)[/tex], will return [tex]\( x \)[/tex]. The inverse function [tex]\( f^{-1}(x) \)[/tex] will essentially "undo" what [tex]\( f(x) \)[/tex] does to [tex]\( x \)[/tex].

### Step-by-Step Solution:

1. Start with the given function:
[tex]\[ f(x) = \frac{x + 2}{7} \][/tex]

2. Replace [tex]\( f(x) \)[/tex] with [tex]\( y \)[/tex]:
[tex]\[ y = \frac{x + 2}{7} \][/tex]

3. Swap [tex]\( y \)[/tex] and [tex]\( x \)[/tex] to begin finding the inverse function:
[tex]\[ x = \frac{y + 2}{7} \][/tex]

4. Solve for [tex]\( y \)[/tex] in terms of [tex]\( x \)[/tex]:

- Multiply both sides of the equation by 7 to clear the fraction:
[tex]\[ 7x = y + 2 \][/tex]

- Subtract 2 from both sides to isolate [tex]\( y \)[/tex]:
[tex]\[ y = 7x - 2 \][/tex]

5. Thus, the inverse function [tex]\( f^{-1}(x) \)[/tex] is:
[tex]\[ f^{-1}(x) = 7x - 2 \][/tex]

6. Identify the function from the given choices:

- A. [tex]\( p(x) = 7x - 2 \)[/tex]
- B. [tex]\( q(x) = \frac{-x + 2}{7} \)[/tex]
- C. [tex]\( r(x) = \frac{7}{x + 2} \)[/tex]
- D. [tex]\( s(x) = 2x + 7 \)[/tex]

From the above steps, it is evident that the correct inverse function is:

A. [tex]\( p(x) = 7x - 2 \)[/tex]

Therefore, the correct answer is choice A.